Stabilized composition



Patented Aug. 23, 1949 STABILIZED COMPOSITION.

Daniel B. Luten, Jr., and Aldo De Benedlctis, Berkeley, Calif., assignors to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application January 25, 1947,

Serial No. 724,470

13 Claims.

As is known, gasoline obtained by cracking socalled heavy petroleum oils considerably changes its properties when kept in storage. Such changes affect the value of gasoline as a motor fuel and often render it entirely unsuitable for this purpose. In the following disclosure, all substances which stabilize reformed (cracked) gasoline will be called, for brevitys sake, inhibitors In the past, it has been recommened to add various inhibitors to unstable gasolines to improve their storage stability. Among the active inhibitors are particularly the alkylated phenols, aromatic amines and hydroxy amines, etc. While many of these inhibitors have a limited beneficial effect upon the stability of cracked gasblines, unduly large amounts of the inhibitors are sometimes required in order to obtain satisfactory stabilization, thus leading to the formation of engine deposits when the inhibited gasoline is used as fuel. Again, some of the proposed inhibitors have only a limited efiect, irrespective of the amounts added to gasoline. In order to be outstanding, an inhibitor must be capable of stabilizing gasoline satisfactorily when present even in-extremely small amounts.

It is an object of this invention to provide an outstanding class of gasoline inhibitors. It is another object of this invention to provide gasolines of exceptional storage stability. It is a further'object of this invention to provide gasoline compositions having little tendency to form gum deposits. It is a fourth object of this invention to provide gasoline compositions having exceptional color stability. Other objects will become evident during the following disclosure.

Now, in accordance with this invention, it has been discovered that one class of inhibitors is superior to any others tested for the stabilization of cracked gasoline. These inhibitors are substituted dihydroxydiphenyls having the general configuration n a R a H 011 wherein one R. attached to each pheny radical is any alkyl group, preferably an lkyl group having alkylated phenols having alkyl groups attached to the two carbon atoms adjacent to that linking the phenolic hydroxyl group. Such alkylated phenols have the general configuration R 1 a a wherein R1, R2, R3 and R4 are dissimilar alkyl groups and each phenyl radical contains at least one primary or secondary alkyl group.

The symmetrical type of inhibitors represented by Formula 1 above may be prepared by the oxi; dation of a, single 2,6-dialkyl phenol wherein the alkyl groups are identical groups of primary or secondary configuration. Such diphenyl derivatives include 3,5,3,5-tetramethyl-4,4dihydroxydiphenyl, 3,5,3',5' tetraethyl 4,4 dihydroxydiphenyl, 3,5,3',5' tetrapropyl 4,4 dihydroxydiphenyl, 3,5,3,5-tetraamyl 4,4 dihydroxydiphenyl, 3,5.3',5 tetrahexyl 4,4 dihydroxydiphenyl, 3,5,3',5 tetraheptyI-4,4' dihydroxydi- :phenyl, 3,5,3',5'-tetraoctyl-4,4-dihydroxydiphenyl, 3,5,3,5-tetranonyl 4,4 dihydroxydiphenyl, 3,5.3 ',5' tetradecyl 4,4 -'dihydroxydiphenyl, 3,5,3',5' tetradodecyl 4,4 dihydroxydiphenyl, etc.

Inhibitors having the general configuration of Formula 2 above may be prepared by the simul-' taneous oxidation of two 2,6-dialkyl phenols, each having at least one alkyl group of primary or sec-. ondary configuration, one of which phenols has dissimilar alkyl groups, the other of which has alkyl groups which are both identical with one of said groups of the first phenol. This type of 3 v inhibitor is illustrated by such diphenyl derivatives as 3,5',5'-trimethy1-5-ethyl-4,4-clihydroxydiphenyl, 3,3',5-triethyl-5-methyl-4-4'-dihydroxydiphenyl,

4 3,5-diamyl-3'-ethyl-5'-methyl-4,4'-dihydroxydl phenyl, 3,5-dihexyl-3-methyl-5' isopropyl 4.4 dihydroxydiphenyl,

3,5,3-tripropyl-5'-butyl-4,4'-dihydroxydiphenyl, 6 zij ggg dihydmxy' 3,5.3-tributyl-5-methyl-4v4' -dihydroxydiphenyl, 1 531 5! triamyl 3 lsopropyl 4 4 ih d 3,5-dlOCty1-3 -ethYl-5 -heptyl-4,4 dihydl'OXYdi diphenyl, phenyl, 5,325-trihexyl-3-amyl-4,4-dihydroxydlphenyl, 10 ig gi 'methyl's 'dmydmxyd" 3,5,3-triheptyl-5-ethyl-4,4'-dihydroxydiphenyl, n 3,5,3'-trioctyl-5'-butyl-4,4'-dihydroxydipheny1, 55323 dihydmxydi 3,5,5-trinonyl-3'-heptyl-4,4'-dihydroxydiphenyl, 3,5,3'-tridecyl-5'-methyl-4,4'-dihydroxydiphenyl, 3I5-dIdOdeCYI-3 'methyl 5 duly- 3,5,5'-tridodecyl-3-ethyl-4,4'-dihydroxycliphenyl, droxydiphenyl' t 15 Another preferred configuration of the subject Formula 3, given above represents alkylated gasoline inhibltors is that of Formula. 5, given dihydroxydiphenyls which may be prepared by hereinbefore. Inhibitors of this category may be the simultaneous oxidation of two symmetrical Prepared y the Oxidation Of a single unsymmetzsdialky} phenols the alkyl groups of one phenol rical 3,5-d1alkyl phenol having at least one alkyl differing from those of the other phenol but each gm?!) of primary or Secondary configuration phenol having at least one alkyl group of primary hibltof's of thls type are or secondary configuration. Inhibitors having 3,3'-dimethy1-5,5'-d yl- 3'dr0 y P this type of configuration include y 1 i 3,5-dimethyl-3 5'- iethyl-4,4'-dihydroxydiphenihgifs l dflsopmpy 4,4 -dyhydmxydi y], I r 3,5-diethyl-3',5'-dipropyl-4,4'-dihydroxydiphen 'i gif f methyl dflydmxm yl, r r I 3,5-diisopropyl-3,5'-dimethyl-4,4 dihydroxydi- 1 21 3 buty] methyl 'dihydxoxydl phenyl, 3,5-di-tert-butyl-3',5'-diethyl-4,4' dihydroxydi-- methyl d-mydmxydlphen phenyl, I 3,5di-n-amyl-3',5' dibutyl 4,4' dihydroxydi igfi diiwpmpyl dihydmxyd ph ny 3,5-dihexyl-3',5'-diisopropyl 4,4 dihydroxydi- Y1 diheptyl methyl d-mydmxydlphen Phenyll 3 s' dieetyi-s 5'-dibutyl-4 4'-dihydroxydiphenyl 35-dihePtY1"?15'-dieth$1-414"dihYdr 3 3-dinonyl-5 5-di-sec-bl 1tyl-4 4' dihydroxydh- Y r v i phenyl, 3,5-d1octyl-3',5-cl1amyl-4,4'-d1hydroxyd1phenyl, n m 3,5-dinonyl -s',5' -dimethyl--4,.4 dihydroxydi- 4o dimethyl dihydmxydiphe phenyl, l 3,5-didecy1-3",5'-dimethyl-4,4'-dihydroxydiphen i mmyl dhydmxydpm r Another class of the subject'inhibitors is re- 3,5- e l-3,5 -det l-4,4- ih roxd- 12233 g I by d yd y l presented by the general Formula 6, given here I inbefore, and includes such inhibitors as B-meth- Another suitable type of inhibitors, having the 1-5 th 1 3'..1 1-5' b t 1..4,4' dihydrgxygeneral Formula 4, given above, may be Prepared diphenyl, etc. Mixtures of the above inhibitors by the simultaneous oxidation of two diiTerent may be 2,6 i l y1ph n one of whi h is ymm When used in the average cracked gasolines, the other of whlch unsymmetrical. the alkyl inhibitors having the general configuration of groups of the first dlfiermfg from those of the the present invention are effective in relatively second but each phenol having at least one alkyl Small amounts; usually from about 00 to group of primary or secondary, configuration. about by weight Representatives of this configuration are EXAMPLE I .5- d1 e y y '-P pY dihydroxy For matters of comparison, and to show the ph y I critical nature of the configuration of the ine y y -D 0py dihydroXy hibitors of the present invention, the efiectived phe y ness of the various phenyl derivatives listed below S h ODy y ethyl d y 00 are related to that of cresylic acid, a well-known d q ydlpheny gasoline inhibitor. The inhibitors were added 3,5-d1butyl-3'-methyl-5'-propyl-4,4' dihydroxyto cracked gasoline and tested by the standard diphenyl, oxygen bomb test.

Table 1 Inhibitor concen- Effectiveness tratlon required Rclativeto Inhibitor ltdtttittteti 9562?? of the gasoline! hours Cresylic acids 17.0 3,3,5,5-tetramethyl-4,4-dibydroxydiphenyl 1. 05 16. 2 3,3-dimethyl4.4-dihydroxydiphenyl 3. 0 5. 6 4,4'-dih,vdroxydiohenyl 15.6 0.91 3,3,5,5-tetramethoxy-4,4'-dihydroxydipheuyl.. 6. l 3. 3

V Exlmrts II A cracked gasoline of different origin from that used in Example 1 was inhibited with the variprising cracked gasolin and from about 0.001%

to about 0.1% by weight of 3,5,3',5'-tetramethyl- 4,4-dihydroxydiphenyl.

2. A cracked gasoline stabilized by the addition thereto of a small amount of 3,3'-dimethyl-5,5'-

di-tert-butyl-4,4'-dihydroxydiphenyl.

3. A cracked gasoline stabilized by the addition Table 2 Inhibitor Concentration required Effectiveness )1 hi to increase the Relative to In 1 tor InductionPerlod Cresylic oi the Gasoline 4 Acids hours Cresylic Acids l8 3,35,5'-tetrametbyl-4,4'-dihydroxydiphenyl 3 0 3.3'-dimethyl-5,5-di-tert-butyl-4,4'dihydroxydiphenyl- 4. 2 4. 3 3,3'-diethyl-5,5'-di-tert-butyl-4,4-dihydroxydiphenyl 4. 8 3. 8 3,3'-5,5'-tetra-tert-amyl-4,4'-dihydroxydiphenyl 21. 5 0. 85

While the subject inhibitors have been found to be particularly suitable for use in cracked gasoline, they also constitute satisfactory staing oils, hydrocarbons, hydrocarbon polymers,

and other oleaginous materials, such as benzene, turpentine, corn oil, cottonseed oil; animal oils such as neats-foot oil and lanolin; fish oils such as sperm oils; synthetic cellulose derivatives such as ethyl cellulose, cellulose acetate, hydroxyethyl cellulose, carboxymethyl cellulose and cellulose nitrate; polymers of unsaturated materials, such as acrylic acid ester polymers, methacrylate polymers, polyvinyl compounds, polystyrene;- fats, oils and soaps; aromatic amines, dienes, terpenes and other naval stores. The statements as to properties and proportions as discussed hereinbefore in connection with cracked gasoline apply here as well.

Illustrating the general applicability of the subject inhibitors, the following examples are presented: 7

EXAMPLE III A leaded aviation gasoline was tested for stability as described in Example 1, above. It had an induction period of minutes. Two samples of this gasoline were inhibited with 1 and 2 mg. 3,5,3 ,5 -tetramethyl-4,4' -dihydroxydiphenyl of gasoline per 100 cc. respectively, and then tested for stability. The samples had induction periods of 400 and 4'70 minutes.

EXAMPLE IV A highly refined white oil was tested for star bility by the standard oxygen absorption test, oxygen being bubbled through the oil at 150 C. The times required to absorb oxygen both in the presence and in the absence of inhibitors are given in Table 3, below:

thereto of a small amount of 3,3'-diethyl-5,5'-ditert-butyl-4A -dihydroxydiphenyl.

4. A cracked gasoline stabilized by the addition thereto of an alkylated dihydroxydiphenyl having the general formula wherein each R1 is a primary alkyl radical, all of said radicals being identical.

5. A cracked gasoline stabilized by the addition thereto of an alkylated dihydroxydiphenyl hay.- ing the general formula wherein the R1s are identical primary 'alkyl wherein the R1s are identical primary alml radicals and Rzs are identical alkyl radicals dilfering from the Ris.

7. A cracked gasoline stabilized by the addition thereto of a minor amount of a 3,5,3',5'-tetraallryi-4,4-dihydroxydiphenyl wherein each alwl Table 3 Time to Time to Time to Inhibitor absorb 250 absorb 750 absorb 1500 ce. oxygen, cc. oxygen, cc. oxygen,

hours hours hours None 0.3 0.8 1.8 3,3-dimethyl-5,5-di-tert-butyl-l,4-dihydroxydiphenyl 29. 6 31. 0 34. 1 3,5,3'-5-tetramethyl-4,4-dihydroxydipbenyl 17. 3 17. 6 18 0 We claim as our invention: 1. A stable cracked gasoline composition comradical is a primary alkyl radical having from .one to twelve carbon atoms.

8. A cracked gasoline stabilized by the addition thereto of a minor amount of a. 3,5,3',5'- tetraalkyl-4,4'-dihydroxydiphenyl wherein each phenyl radical bears at least one alkyl radical selected from the group consisting of primary alkyl radicals and secondary alkyl radicals.

9. A liquid petroleum hydrocarbon stabilized by the additinon thereto of a minor amount of a 3,5,3',5 tetraalkyl 4,4 dihydroxydiphenyl wherein each phenyl radical bears at least one alkyl radical selected from the group consisting of primary alkyl radicals and secondary alkyl radicals.

10. An unsaturated liquid hydrocarbon stabilized by the addition thereto of a minor amount of a 3,5,3',5'-tetraalkyl-4,4-dihydroxydiphenyl wherein each phenyl radical bears at least one alkyl radical selected from the group consisting of primary alkyl radicals and secondary alkyl radicals.

, 11. An unsaturated liquid hydrocarbon tending to oxidize and form gummy substances stabilized by the addition thereto of a minor amount of a 3,5,3,5'-tetraalkyl4,4'-dihydroxydiphenyl wherein each phenyl radical bears at least one alkyl radical selected from the group consisting of primary alkyl radicals and secondary alkyl radicals.

12. A leaded aviation gasoline stabilized by the addition thereto of a small amount of 3,5,3,5',-tetramethyl-4,4'-dihydroxydiphenyi.

13. A highly refined white oil stabilized by the addition thereto of a small amount of 3,3'-dimethyl-5,5'-di tert butyl 4,4 dihydroxydiphenyl.

DANIEL B. LUTEN, JR. ALDO DE BENEDICTIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

